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UNITED STATES PATENT OFFICE;

WILHELM HIRSCHKIND, OF PITTS BURG, CALIFORNIA. ASSIGNOR TO CALIFORNIAALKALI COMPANY. OF SAN FRANCISCO. "'ALIFORNIA, A CORPORATION OF CALI-FORNIA.

PROCESS FOR THE RECOVERY R PURIFICATION OF POTASSIUM SALTS.

To all whom it may cow-mm.

Be it known that I WwnnLM-IImsoH- mNn, a subject of the King of Bavaria,and

a resident of Pittsburg, county of Contra Costa. State of California,have invented certain new and useful Improvements in Processes for theRecovery or Purification of Potassium Salts, of which the folloumg is aspecification.

My invention relates to the recovery or purification of potassium salts,and more particularly to the recovery of potassium cblorid from naturalbrines or nuxturcs ontaining potussilun chlol'id and boracir compounds.with or without other salts. lolas ium salts. more particularlypotassilun chlorid occur in many natural waters such as those officarlcs Luke, Owens Lake. and .ln-lm lrahc. n ('alii' rnin, togetherwith salts ol' boracic will such as bornx'.

This application is a continuation in part of iny prior :IppIi ntiouHer. No. 175792 liled June 20, H ll The iuh-nlion is especially usefulin the recmcrv of potassium chlorid purified oi borax or boraciccompounds, from brines or saline .liquors' "ontainiug those ingre-Ylic'nts. such for example as the briucs of lhe aforesaid lakes.

-()f cmuxwntheinvention may be used to purify potassium saltscontaining, boraclc compomids. to free it o! the bommno'mat tcr 10\\'.he ililpurc potassium salts are ob lainell it. ma alao be an object toobtain certain of lhe otber salts, including borax, the invent-ion notbeing specifically limited u. obtaining potassium chlorid only.

The processes which have hither to been used in the preparation ofpotassium salts l'r e from boracic compounds have been to (boos andexpensive; various attempts having been made to separate them in thestate in whiclrthey occur; I have discovered that bv con vertino one oftbesc constituents. leaving the other unail'ectcih into a form in whichit is capable of ready solution while the oihcr mnstitucnt remainsinsoluble, the coln'crtcdconstituent can be readily separated.

In other words, my invention broadly comprehonds the practical treatmentof mixtures containing potassium salts and boron so as to convert one ofthe components into .l form which 'is amenable to a selective sol-Specification of Letters Patent.

tion of the bicarbonate of sodium.

treatment of the liquor with carbonic acid- Patcnted J une 15, 1920.

Application filed April 8, 1915. Serial No. 227,317.

vent agent, and then recovering the dissolved constituent which had beenso converted. My process is particularly directed to the removal of theboracic ingredient by simple and inexpensive means.

I: .ore especially I have discovered that by treating the impurepotassium salt (one having the boracic compound mixed therewith) with onacid or an acidic substance, such for exai'nple as sulfur dioxid, orchlorin, to liberate the boracic acid in the free state, and thentrcatinp the resulting potassium salt obtained from this liquid and nowcontainin; boruclencid, with a solvent, which has a selective solventaction upon boracic acid and potassium chlorida solvent such for exampleas certain alcohols, ethyl or methyl alcohol, the boracic aciddissolves, leavinp the potassium salt free from boracic acid.

The alcoholic solution may then be recovered for further use, bydistilling it, prefer ably after adding an alkali such as soda or lime,to combine with the boraeic acid conmined.

In the latter case. I prefer to evaporate the water to such a degree aswill [)I'Odllljt a separation of the major port of the car bonate andbicarbonate of sodium and of the smlilun chlorid and sulfate generallycontained in such waters. This may genorally be accomplished byevaporating the water to a. certain concentration and trcating it withcarbonic acid gas for the separa This gasi. (1., carbon dioxid willtransform the carbonate to an insoluble bicarbonate Tfrom which theliquor is removed. This is followed by further evaporation to separatesodium chlorid and sulfate. In case the sodium carbonate has not beensufiiciently removed by the first treatment with car bonic acid gas,there may be a second treatment of the l'u'uor, (now further concen-.

trated) with car onic acid gas (5. 2., carbon be done by solar heat andsubsequent boiling, or by boiling alone until the saturation point ofpotassium chlorid in that solution at ordinary tem erature is reached.

Different mo es of procedure are desirable in the next steps, dependingupon whether the proportion of boracic compounds as compared with thepotassium compounds is large or small. The hot liquor separated fromcommon salt and sulfate and saturated with potassium chlorid at ordinarytemperature, may in case the proportion of borax is large, be allowed tocool and deposit crystals of borax.

In case the proportion of horax is so small that the concentrated liquorobtained at this point will not deposit pure borax, the liquor may betreated directly with an acid, for example, hydrochloric acid, whichwill sepa rate the boracic acid from the sodium with which it has beencombined. When the pro-- portion of hornx is large, the mothcr liquorremaining: after the crystallization of tho horax. is treated with acidin the same man-- nor as just described. instead of hydrochloric acid.any chemical may he nsr-d which will libel-atrthe l)l)l'.'l('l(' a id;for example, sulfuric acid, acetic acid, rhloi'in or sulfur dioxid.

In some cases it may be desirable to carry the concentration oi thisliquor (hcl'orc add ing the acid which is to liberate iluhoracnucid) tothe point of saturation of potassium clllorid at the temperatureemployed and then to cool the liquor \vhcrehy crystals of p tassiumchlorid and hornx separate from the solution (which solution returned toan original liquor being treated). and then to rcdissolvc lhcsc crystalsin water. the rcsnlb in; solution hcing; then treated with an acidv III.

The solution now containin the lotussium salt as well as the freehoracic acid, is

The solid crystals thus produced are now treated with an alcohol, suchfor example as methyl or ethyl alcohol. until the boracic acid iscompletely rcn'ioved. ()thcr impurities containedin the potassium saltssuch as sodium chlorid, may be removed by leaching with cold water.

Instead of conducting the evaporation in such a way as to produce asolid mixture of potassium salt and boracic acid, the solution may insome cases be'evapor'ated to a concentrated state and the alcohol addedto this solution in such amount as to com letely dissolve the borne-1oacid andleave t e maor part of potassium salt undissolved.

The alcololic solution ct'intnining the horacic acid may then berecovered for further usc by distilling it. preferably with the additionof some alkaline substance, such as soda or lime.

While I have described my invention according to the prci'crrcd mannerof practisinn the same, it will be obvious to those skilled in the art,after having understood my invention, that certain steps or phases ofthe complete process described may be utilized without utilizing thewhole process described, according to the work tobe ac complished, andthat certain substitutions and changes may he made in ertain phases ofthe process without departing from the spirit or scopc oi my inventionand (liscorery.

Having thus dcsrrihcd my invention, what I claim as new and desire to scur-c by Lettcrs latent, is

l. 'lhc pro ess oi separating from a mixturc contz'iiuing potassiumsalts and boraciiacid, the potassium salts, which comprises treating themixture with an alcohol to extract the boracic acid.

3. The proccss of separating horacic acid from impure potassium chloridcontaining box-uric acid, which commiscs treating the pol, jlillllllchlorid with an alcohol for the removal of the boracic acid.

2-3. The process of purifying potassium chlorid from horucic acid, whichcomprises treating the solid potassium chlorid containinnhoracic acidwith an alcohol for the remov ali of the borucic acid.

4-. The process of purifying potassium chlorid contaminated with boraciracid and one or more water soluble salts, which comprises treating thepotassium chlorid with an alcohol for the removal of boracicacid, andthen leaching with water thepotassium chlorid crystals remaining: todissolve out any water soluble salts.

5. The process of separating, out of a mix ture containin c a otassiumsalt and a horacic compound, tie potassium salt, which comprisestreating the mixture with a reagent that will lihera tc boracic acidfrom its salts in a free state, separating; from the solution a mixturecontaining boracic acid and potassium salt, and treating the separatedmixture, containing boracic acid and potas-i sium salt, with a solventthat will extract the horacic acid but which has little orno itlinit forthe potassium salt.

(3. he process of separating out of a miit ture containin potassiumchlorid and sodium borate, t e potassium elilorid, which comprisestreating the mixture in solution.

with a reagent which. .will' liberate the boracic acid from its procombination, and then recovering, in slili rm from the solution, thepotassium chlorid mixed with boracic acid, and treating the recoveredmixture. containing the potassium rhlorid and boracic acid, with asolvent that will combine with the boracic acid but which has little orno allinity for the potassium chlorid.

T. The process of separating out of a mixture, containing in potassiumsalt and a. boracic compound, the potassium salt, which comprisestreating the mixture with a suituble aciclic substsnce'to liberate thehoracic acil'lfrom its previous combination, scparat ing from thesolution a mixture containing horacic acid and potassium salt, and.treating the separated mixture, containing boracic acid and potassiumsalt, with an alcohol to extract the boracic acid.

The process of recovering potassium salts from waters, which consists inscparating from them an impure potassium salt containing boracic acid orits cornbiinztions treating the impure salt to liberat the boracic acidin the free state and i-ndracting the boracic acid with an alcohol.

H. The process of purifying potassium salts, which comprises treatingthe impure potassium salts with an acid or acidic sub-- stance to freethe boracic acid contained in it from its compounds, and removing theboracic acid by treating: the impure potas sium salt with an alcohol.

n). The process of purifying potassium salts of sodium borate, whichcomprises treating; the mixture in solution with a rcagent which willliberate the boracic acid from its salts in a free' state, separatingthe mixture of the borucic acid and potassium salt from the solution,and treating the sepa rated mixture with an alcohol to separate thebormric acid.

ll. The pun-ass of purifying potassium salts of boracic acid whichcomprises treatin; the impure salts with an alcohol SQPEZ" rating thealcoholic solution and recovering the alcohol by distillation.

12. The process of recovering potassium salts from waters containingsodium car bonate and horacic compounds. which com-- prises treating thewaters at a suitable de' gree of concentration with carbonic acid,separating the sodium bicarbonate formed, evaporating the water for theseparation of crystals of impure potassium salt and treat ing; theimpure potassium salt with an acid or acidic substance to liberate thehoracic acid contained in it from its combination and removing theboracic acid by treatment with an alcohol.

iii. The process of recovering potassium salts from brines containingsuch salts as sodium arboiiate. sodium sulfate. boracic compounds andpotassium salts, which comprises treatin the somewhat concentrated brinewith cai'laonio acid gas for the separation of the sodium carbonate,heating the remaining solution for the separation of the sodium ohlorid,cooling the remaining solution i' or the separation by deposit of sodiumborate, fronting the remaining solution with an acidic substance toseparate the boracic acid in a free state, recovering in solid form thepotassium salts mixed with boracic acid, and then treating the crystalswith a solvent that will extract the boracic acid from said solid salts.

14. The herein described method of obtainingpotassium chlorid fromwaters containing the same and sodium boratc and other salts, embodyingfirst partially eliminating: the salts other than the potassium chloridand sodium boraie so as to obtain a solution high in the chlorid andborate, trcatin; the solution with an acidifying agent to form boricacid, depositing the chlorid and acid from the solution, and mparatingthe horic acid thus formed by dissolving in alcohol.

The herein described method of obtaining potassium chlorid tron waterscontaining thesaine. and sodium bora e, sodium chlorid and other salts,embodyisq first eliminating the other salts and concentl ting to obtaina solution high in the three nancd salts, treating the solution with anacidity 111;: agent to form boric acid, cimcentrating the, solution byheat to deposit the named salts and acid, treating the mixed salts withalcohol to dissolve the boric acid formed and'scparating the solutionthus formed, and washing out the sodium chlorid from the remainingmixture of sodium chlorid and potassium chlorid with clear cold water,leaving: the potassium chlorid.

ill. The herein described methoiil of obtaininn potassium chlorid fromwaters con taining the same and sodium borato and other salts,illllnfn,i}'ll1 f first partially climb nating the salts other than thepotassium chlorid and sodium borate so as to obtain a. solution high inthe chlorid and borate, conccntinting the solution by evaporation.depositinglhe ehlorid and borate by cooling the cruicentrated solution,separating the mother liquor from the deposited salts and redissolvinp;the salts in clear water, heating the solution with an acidifying agentto form boric acid, depositing the chlorid and acid from the solution,and separating the horic acid thus formed by dissolving in alcohol.

17. The herein described method of obtaining: potassium chlorid fromwaters containing the same and sodium borate. sodiiun cl lurid and othersalts, embodying first oliniinating the other salts and concentrate ingto obtain a solution high in the three named salts, concentratingtliesolution by Ill) the 1 larlcpmitcd salts and rofiii-Sb ll't'lilgj thosaith 1n vlvar water, treating tho solution with an acnlityingg' aux-n1lo form horicacid zwin -viuralingg the till ion l e aporati n to lhri:-xit tho uun'ual salt:- EHl-Il :uivl m-purating and iltfz'tlillg lhc hposih-d acid and who i alcohol to dim solve thc luu'ir and nomad; andwpara iog the solution thou foruuul. and washing out tho sodium rhlorillfrom tho ronaaiuing nil;- EH1? of sodium hlorivl and potassium chlorivlwith vinaicold wuarr. halving; lhc llll i -llllll liiiifillil,

15. The luu'ciu dwcriht-d llkffii ilifli ol' r =ating wmors containingpotassium chlorid'. so (llllfll horate, sodium sull'atc. M'ltlllllll rawhouate am. sodium chlorid nzhodyiug lirst concentrating by e\ apo nationto removv part of the sodium (-hlorid, sodium carbontv and sodiumsulfate to ohtain a bfilllllfll'l strong in sodium borate and potassiumclilorid. tho ((ll'l'fl-lltlatlfin being! pror-uudvd with to thoSaturaiion point of potassium chlorill ai' ilil tempcraiuro oinplovml.rcmoving tho liquor from the ilvposiivd salts, tlwn trialling thosolution with an ucitlifviu r rvagzvul to Form bori' filiifi; thencoiu's-nl'iating' Lhc liquor to deposit the ('llflllull'ltll Sillih andarid. ucpa rating and troatinrthv uiixi-d salts-,1 and a id with ahoholLo Lllrififll'x'i the horir' acid v moving tho solution od wishingoutllll' remaining Sulfa u Ell ilvur nolcl Wul'll' ltili lug tvlu potassiumchi rill uodisholu-rl It Too ln'l'eiu iluuvrihotl nwthod ol illiil ingwaters F nt-inning pOlHSHllHli rhlui l. soiiium liot'atc sodium sulfato.sodium can lI C'IlELEP. and sodium ohlorid, on'ihoilyingg first;concentrating by (wapor ttiou to nouovepart of the sodium 'IflllUl'hl.sodium carhouliand soditun sulfate to obtain a solulion rvlalivelystrong: in sodium lie and pola -zium chiorhl, the conical? n b ing; plo-Booth-(l with to tho natural point of polo SIHIR chlorul at tholoiupfl'aturc cmplo vcd in rw'aporonngi EPIHUYlU Lf tho liquor from thoclepositeil salts. drp siling thiialts from (h:- liquor v cooling.rciuovii'sg the liquor from the dwmitml salt. IHllSSfilVlllg tlwvililt'li itml salts in cit-av water Hulii nuu to main :1 Solution: thoutreaiing tho solution with an acidifying rcagcnt to form horir avid thanconcentraiinq the liquor to deposit tllc m tainctl aks and aciihrvmoviug and iroating' the n'uxaul suit and acid with ah-ohol lo (ilk?fs'UlVi tho lmriv -id. ronioving tho soluiliou from tho ruin-aimingHalf). and washing out the remaining sails with (Iiiiii' oh! wattaloain; he potaw 'Lm rlilorid 1!l ll t-!l vial.

u eliuiu sulfato to ohta in a solution ri-lativol)" ulaxong inFUllllllll horatv and potassium a lilorid, oooling to deposit a portionof tho diuiu horatc, removing the liquor and proll mllllg with thcconcvntrating to tho saturalull point; oi potassium chloriil at thetoni- }a-i'2liii5(* employed, rcmovii'u: the liquor from the depositedsalts, depositing the salts from llio liquor by cooling", i'iunoving theliquor from the deposited salts. redissolving tho deposited salts inrlcar water sufficient to lllrllfl a solution: thcn treating thesolution with an aridil'ying roagcnt to form horiv acid. tlu-nconcentrating the liquor by evaporation to \loposil; the contained saltsa llll acid, removing and treating the mixed salts and acid with alcoholto dissolve thc horic avid. removing lhv solution from tho vcuiaiuiugsalts, and washing out the Pomainin g salts with clear cold walrrleaving thv potaasiluu chloriil IlINllSbOlYPll.

Jl. 'lhc hvrciu (lPSCliliWl pror-css of trout: in; YHKLIZS Containingpotassium rhlorid. so dium horatc, sodium suli'utc. sodium carbonate,and sodium chlorid. muhodyinofirst tr ating tho liquor with cal-l onlllUX lll to transform thc carhoualc to an insoluhlc hiionatiandrviuovizug thc liquor thoroiroiu, {hon healing and evaporating tholiquor to concvutrato it to the saturation point of potassium rllloridat ordii'iary tour pvralurcs. thou treating tho liquor lurthcr withvarhon dioxid to removu further so llllm carbonate and tlwu coolin; lodeposit sodium horate and roniovinp tluliquor, thou l'urlhcrQom-vnlratilig tho liquor hy cvaporation to tho salu ation. point ofpotassium chlorid at the toinpcraturo en'iployml, thou milling theliquor to dvposit tluvo'utvaiuml Hillih rvinoving tho liquor to hereturncd to an original liquor hcing trcatvil. rcwlissolvlugthr mixedhalls in clear water. trcatiug lluhUlllllUll with chlorin to form horicacid and sodium chlorid from the sodium horattx l'llil fi'llll'ililllgthe solution and depositing tho aaltu a [El horic acid therofrouurvnioving and troatlug tho mixcd elopoz-ait with alcohol to dissolve thehorio acid and removing the solutioiu and washing out the salts withclear cold \vator leaving undissolved lhv p iasuium chlorid.

in ti-atimony whereof, I have signod mv nanut to this specification.

VI Ll ELM H l RSCH Kl N1)

